Blast nozzle



Dec. 26, 1933. w. G. SCHWARTZKOFF BLAST NOZZLE Filed July 9, 1931 e/ 5/ HZ /0 Ruezzlar h aiier wv/zmrg/m Patented Dec. 26, 1933 f UNITE srArss AY ENT [OFFICE LASTNOZZLE: Walter Schwartzkopf, strains, ivr f v ApplicationJuly 9, 1931.,seria 1 No. 549,608

2 Claims. I (Cl."5l-'l1 7 This invention relates to new and useful im The primary objects of my invention are to provide a'nozzl'e; the discharge mouth oropening of :which is not more than"0.075 of an inch in diameter so that the, abradant material is discharged therefrom ina stream which canbe used in inscribing or blasting on stone letters or designs of fine proportions.-

Otherpbjects ofithe invention are to provide an improved nozzle which is highly efficient in operation and is so constructed that the wear thereon by the abradant material is reduced to 1 minimum, thereby prolonging the life and usefulness of the nozzle. l p I Additional objects of they invention'are to provide a nozzle holder which can beconveniently held by the operator in-inscribing letters and fine designs on stone and wherein the parts most subjected to wear are formed detachable and can be replaced when worn. 1

With these and other objects in view, my invention consists in certain novel features of cons'truction and arrangement of parts hereinafter more fully described and claimed, and illustrated in the accompanying drawing, in which- Figure 1 is a side elevational view of my'im-' proved holder having attached thereto a flexible .hose connection supplying compressed air and abradant material and provided with adischarge' r from the nozzle for a given period of time.

nozzle of my improved design.

Figure 2 is an enlarged longitudinal cross section through the holder and the nozzle.

tion through the nozzle. 0

Figure 4: is an end view of the latter; Referring by numerals to the accompanying drawing. '10 indicates a holder provided with 5d. a longitudinal bore 11 and having one end formed at 15 for receiving the threaded end 16 of a detachable nozzle 1'7.

The outer end of connector 14 is internally threaded to receive a suitable hose connection 18 which leads from a source of compressed air and abradant material (not shown). The ma- Figure 3 is-an enlarged longitudinalv cross secv teri'al used is preferably fine shot but sandmay be used, if desired.

I The inner end of connector 14 is tapered outwardly, as indicated at 19, so that whenysaid connector "is attached to the holder a suitableclearance is provided between the shouldered portion .20 of theholder and said tapered end so as to receive any abradantmaterial'the'rebetween and insure at all timesa close fit adjacent'to the peripheral-surfaces of said parts. The boreof said connector 14' 'is provided with a circular shoulder 21 against which the end of extension 12 is brought when theconnector is screwedon tosaid holder. Thus a .bore chamberuniform in diameter is provided between'the connector andthe holder and the end :of eiitensionlz is protected by said shoulder. against the abrasive action ofthe material traveling through said bores. i p

The enlarged threaded bore '15 of the forward end ofthe holder is provided with a shoulder'22 against which the inner or threaded end of the f 1 nozzle is located when the latter is screwed in position on the holder. Thus a smooth bore connection is-provided between the holder and the nozzle and the inner end of the latter is protected against wear by the action of the abradant material.

. The bore of the nozzle is tapered outwardly,

as indicated at 24. A suitabledistance from the mouth or discharge end 25 of the nozzle (in the present case for a distance of about one-eighth of an. inch) the bore is formed straight, as indicated at 26, and is 0.075 inches in diameter which is also the size of the discharge mouth or end 25.

Thus it will be observed that the nozzle has a comparatively outwardly tapered bore which terminates in. a short section of straight bore and v of small diameter; This causes alarger amount of shot or abradant material to be discharged The short sectionof straight bore of uniformdiameter with the'discharge mouth or opening protects the latter against undue wear and insures the discharge of the abradant material in a stream capable of being used for feather edge 'work on stone. 7

In a nozzle having a tapered bore throughout 7 its entire length the stream of material immediately upon issuing from the nozzle spreads out or diverges outwardly, whereas in my improved nozzle, due to the short terminal portion 26 being formed straight, the material issues from the. nozzle in a fine stream, which for a short distance fromthe nozzle continues in a straight line, thereby enabling the use of the nozzle for fine or feather edge work in close proximity to the stone.

The holder is provided with knurled peripheral 5.3 1' d bore hose connection 21 by means of which the abradant material is supplied to the tool.

Preferably the nozzle 17 is case hardened so as to make it wear-resistant and prolong the life thereof. The particular construction of the nozzle, including the tapered bore 24 and the straight discharge portion 26, the diameter of which latter is not more than 0.075, causes the shot to be discharged from said nozzle in such a mannerv thatfine designs can be worked upon the stone. This kind of work cannot be performed with the nozzles now in use. The holder is'so arranged that it can be conveniently held in the hand without tearing the fingers. As both the nozzle and, the connector are detachable they can be replaced when worn out at small cost, thereby eliminatingthe necessity of discarding the whole m 1;

'I claim: v V 1. In a device of the class described, the combination of "a'tubular holder adapted to be held by the operators fingers similarly to a pencil, said holder having a tapered forward end and a bore of uniform diameter throughout its length and terminating in the forward end in an eninternally screw-threaded, said holder having a reduced rear end provided with an external screw thread, a nozzle having an extension formed with an external screw-thread for detachably engaging the internally threaded I bore of the forward end of said holder, said nozzle having a tapering bore, the largerend of which is of the same diameter as the bore in said holder and the outerend of which termiand uniform diametena connector having one end internally screw-threaded for detachably engaging the reduced rear end of said holder, and

a flexible hose connected to said connector.

between the operators fingers in the same manner as a pencil, said holder having .a tapered ates in a short bore of comparatively small a 2. In a device of the class described, the com- ,bination'of a tubular holder shaped to be held forward end and a peripherally disposed concave portion under said forward endybounded on each sideby knurled portions'to, providea firm finger grip, the rear end of said holder being provided with an internally threaded extension.

and the forward end'being tapered, and having an enlarged bore internally screw-threaded, a discharge nozzle having one end externally screw-threaded for detachably engaging the. threaded bore of saidholder, said nozzle having a forwardly tapering bore,,the inner end of. which is of the same diameter as the bore of Saidlholdl and the outer end of which terminates in a straight short bore not more than 0.0'Z5inches in diameter, a connector having an internally screw-threaded end for detachably 'engagingthe externally screw-threaded end of said holder, and a flexible hose detachably connected other end of said connector.

WALTER G. SCHWARTZKOPF.

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